The present invention relates to an arrangement, according to the preamble to claim 1 for transporting and preferably for monitoring test tubes automatically between the various process stages and equipment in laboratories.
The invention also relates to a method for transporting test tubes.
In analysis laboratories, it is necessary to handle large number of samples and to transport them between different process stages and analysers. The samples are placed in test tubes, which are loaded into and removed from the conveyor racks of centrifuges and analysers, with the samples in one test-tube being distributed between others and the test tubes being finally removed and disposed of. The transport and handling of test tubes has been largely carried manually, but various automatic handling systems are increasing in laboratories, due to the increase in the number of samples and the efficiency of analysers. The basic requirements for an automatic conveyor system are the reliable and undamaged handling of test-tubes and the reliable monitoring of the samples in the system. Reliable handling is usually implemented by placing the test tube in a separate transport base, which is guided as it is moved by a conveyor belt along a mechanically delimited track. The position of the test tubes within the system is monitored with the aid of barcodes and code readers. Publication U.S. Pat. No. 5,605,218 discloses a conveyor track, in which the transport base is moved in a U-shaped groove with conveyor bands running in its comers. The bands have a circular cross-section and are arranged to run as parallel continuous loops. The round bands can be arranged to run along complicated tracks, allowing them to be used to create various routes for the movement of the transport bases. The transport bases can be moved from one track to another, by means of cross-track pushers. In this solution, a single conveyor-loop pair forms part of one track, which must be designed in the shape of the desired route, so that the completed track can only be altered by entirely reconstructing a single track section. The devices for transferring the transport bases from one track section to another are extremely simple and can be used only to move the bases between two parallel conveyor sections and only in one direction. Thus, this solution is only suitable for applications, in which there is little variation in the route of the samples, and in which the samples are handled in a fairly precise order. It is difficult to alter or extend a completed track, as this requires entire track sections to be replaced. U.S. Pat. No. 5,657,856 discloses a solution, in which a conveyor system similar to that described above can be made partly modular, with the system formed by two round bands forming a single module. The modules are connected by means of plate belts synchronizing the movement of the round belts. The connecting units are quite complex and are unnecessarily expensive, because they also include electric motors to drive the belts.
Canadian patent application 2,216,052 discloses a system for handling test tubes containing bio-samples. In this solution, there are at least two transportation lanes, along which the test tubes, located in transport bases, are moved. The transportation lanes comprise plate belts that move the bases, with guide walls and partitions at the sides of the belt, to divide the belt in the centre into lanes. Each test tube has a barcode attached, which permits monitoring of its location and examination of the operations to be performed on it. The apparatus includes the necessary number of barcode-reader stations to read the barcode. As the barcode""s position on the surface of the test tube cannot be known in advance at the reading station, each station has devices to rotate the transport base with the test tube, so the code can be read. This makes the reading station quite complicated and test-tube identification time consuming, which can be a nuisance, if the transportation system capacity must be large, with correspondingly only a short time to process each sample at a each station.
As different kinds of operations, requiring different processing times, are performed on the samples in the transportation system, the system must have devices for altering the order of travel of the samples. In the system referred to above, this takes place by forming two openings, through which the transport bases can be transferred, in the partition dividing the conveyor line. The openings are arranged in connection with an inspection station. In the direction of travel of the transport bases, each parallel lane has first a distribution device for gripping a transport base, followed by a transfer device for moving the transport base through the opening, from one lane to another. The transfer devices are located at the openings, which are on either side of the inspection station""s barcode reader. The distribution device can grip one transport base at a time and prevent the others from moving along the lane, so that an individual transport base can be separated from the rest of the flow. The separated transport base can now be guided to a code-reading station on the other lane or to a parallel lane. This arrangement mainly allows the transport bases to be directed to continue forwards along the same lane, or to transfer them to a parallel bypass or waiting lane. Transport bases can only be transferred between two parallel lanes, but not away from the conveyor, for example, to another crossing conveyor. The system also does not know what sample is coming to the distribution device, so that samples must first be guided to a separate code-reading station, so that they can be directed forwards. As the same reader head is used to identify samples on both lanes, the number of samples the station can handle is limited. Sample identification and direction requires separate distribution devices to break the flow of movement and separate devices to guide samples between the two lanes, but even then samples can only be transferred between two parallel lanes.
The invention is intended to eliminate the defects of the state of the art disclosed above and for this purpose create an entirely new type of arrangement for automatically handling samples, which allows samples to be transferred, in a controlled manner in a single control point connected to the conveyor, if required to several alternative stations, for example, after a delay forwards on the conveyor, to a sample-processing station, to an analyser, or to test-tube filling or removal. A preferred embodiment of the invention is intended to create an arrangement, which uses the sample transport bases to rapidly identify a sample arriving at the control point and decide the sample""s route from the control point to the next transfer or processing stage.
The invention is based on a control station being arranged in connection with at least one conveyor and including at least a handling member, with a grip for gripping a transport base and transferring the base transversely to the direction of movement of the conveyor, to take the transport base from the first processing point, for example, the conveyor, to the following processing point, and devices for preventing the next transport base from entering the control station during the transfer.
The transport bases in one preferred embodiment of the invention incorporate an RF memory circuit, in which data can be entered and read without contact in, for example, a control station, which can then decide which processing point to transfer the transport base to.
According to a second preferred embodiment, a processing device is arranged in connection with the conveyor feeding transport bases to the control station and includes at least one recess to receive a transport base and a surface shaped as a segment of a circle, which is arranged to move into the path of the conveyor, preventing the next base from entering the control station, until the previous base has been fully processed.
According to a further preferred embodiment, at least one conveyor in the arrangement comprises a conveyor-base path bounded by track-like side walls and at least one, preferably two parallel belts set vertically, on the edge surfaces of which the transport bases are arranged to move.
More specifically, the arrangement according to the invention is characterized by what is stated in the characterizing section of claim 1.
The method according to the invention for transporting and monitoring test tubes is, in turn, characterized by what is stated in the characterizing section of claim 11.
Considerable advantages are gained with the aid of the invention.
The invention allows test tubes to be transferred rapidly and reliably between various processing devices, such as conveyor modules, filling and removal stations, operation stations, analysers, and processing equipment. Samples coming to a control station can be transferred to several alternative stations, to the next process stage or to move forwards. A control station can even be used to transfer transport bases to a crossing conveyor or to a conveyor moving in a direction otherwise different to that of the conveyor bringing the transport bases to the control station. If an RF memory circuit is used to identify transport bases and samples, identification data can be read rapidly and, as the small read/write sensor can be located almost anywhere, its location does not restrict the mechanical design of the system. As the position of the transport base does not affect the data entry or reading, the base need not be rotated or otherwise positioned to read the identification data. Thus the handling of the transport bases, at control stations or elsewhere the data in the RF memory circuit must be processed, is extremely rapid. The handling devices of the control station can grip the transport base firmly and the transport base can be moved onto a fixed base, for example, while working with a pipette, eliminating test-tube vibration due to conveyor-belt movement. The handling devices can also be used to centre the test tube reliably in a desired position.
The conveyor components of the arrangement comprise various conveyor modules, in which there is a track preferably delimited by rail-like walls, on the bottom of which two toothed belts are set vertically. The transport bases are arranged to travel on top of the edges of these belts. As the vertically set thin toothed or other belts can turn through a small radius at the ends of the modules, the ends of the belts of sequential modules can come close together and require no other devices to ensure that the transport base will move reliably to the next module. The belts are also in an upright position, so that the outer edges of their turning circles lie next to each other and can almost touch each other, so that the belt does not curve under the conveyor surface, which would form a gap in the conveyor track surface between the belts, corresponding to the turning radius. Modules made in this way can be easily joined as different systems, as they need only be connected to each other structurally and require no connector pieces between them synchronizing movement or containing operating devices. The transport bases are preferably symmetrical around their axis of rotation, so that they need not be in a specific position on the conveyor, but can be freely rotated around their vertical axes by the conveyor or other handling devices. Because reading of the identification data also does not demand a particular position, the bases can be easily controlled. The shape of the transport base fits the shape of the edges of the track in such a way that the bases travel in a controlled manner along the track and are not able to tilt or fall.
The entire arrangement according to the invention permits the formation of a complexly-shaped and easily varied handling system. Damage to a single module will not affect the operation of the rest of the system, so that the entire system will be operational once again after replacement of the module. It is also easy to detach modules for maintenance, replacing them with spare modules for the time required, thus interrupting operation only for a short time. The solution according to the invention is especially advantageous in possible contamination situations, such as blood samples or similar coming in contact with the conveyor system. Normally the conveyor belts will only spread the contents of a sample over the area of a single module, unlike in the arrangement of publication CA 2,216,052, for example, in which the belts extend, through contact with each other, over the area of the whole system, allowing a sample to spread over a very large area and, requiring, in the worst case, the entire system to be cleaned. Sample control is extremely flexible, because both identification and transfer of the transport bases are rapid and certain. Samples can be fed into the system irrespective of the capacities of the individual devices at that moment, because samples can be taken from the sample flow to the processing and analysis equipment according to how many samples the equipment can handle. Waiting samples can circulate freely in the system and bypass the processing points, or be switched to separate buffer modules to wait. As the identification data of the transport base and sample are read whenever the base is handled, the system control unit need not continuously know where individual bases are in the moving flow, which facilitates system control and programming. The track is preferably enclosed, samples being placed on it and removed from it only through the reading points, so what samples are on the track and being processed by the various devices is always known.